The invention relates to a device which safeguards people against falling. To this end, the device has a rail which is supported by holders, as well as a runner which is guided along the rail and functions as a movable attachment point.
Such falling safeguard devices are needed when climbing ladders on broadcasting masts or chimneys, on crane runways, in the field of shipping, for cleaning facades and in similar cases where there is the danger of falling. A ladder with such a falling safeguard device is known from DE-C-1 961 757. A falling safeguard device for ladders is known from EP-A[P]-0 129 241 where an apparatus is provided half way up for horizontal displacement of the attachment point. An attachment device for safeguarding people against falling is known from DE-U-295 17 560 and with which the rail can run both horizontally and vertically. The guide rail for the carriage or the fall arrest equipment has a profiled longitudinal section which is fastened by means of a screw to a mounting bracket which is fastened for example to a crane runway or a roof edge. Falling safeguard devices are also known in which the fall arrest equipment is guided along a rope. Difficulties can arise with such falling safeguard devices from uncontrolled elongation of the guide rope. In addition, there is the visual problem associated with the sag of the rope, which adversely affects the overall visual impression, particularly for facades.
The object of the invention is to create a falling safeguard device which offers complete security against a fall in spite of its comparatively light and filigree construction.
According to the invention, this object is achieved in that the guide rail is mounted movable in the holders in its longitudinal direction.
A floating mounting of the guide rail is achieved through the movable securement of the guide rail so that the rail cannot exert any great force on the holders in the longitudinal direction. When a person falls, the rail is deflected at the attachment point and the overall length of the rail is thereby shortened. The extension of the rail is negligible and the rail acts as a tension bar. The capture impact spreads over the entire length of the rail and is finally conducted into a path force limiter which is provided at one or both ends of the rail. Through the design and construction of the path force limiter(s), the forces occurring when someone falls and the path of the fall can be controlled.
The floating or movable mounting of the rail in the holders is preferably achieved in that the holders partly grasp around the rail and an insert of friction-reducing material, for example PTFE, is located inside the enclosure. As a result, at the same time, an electrical insulation of the rail vis-à-vis the holders and for example the beam of a crane, and a thermal insulation vis-à-vis a building facade (cold bridge) is achieved.
The rail is designed so that it resists a basic load without permanent deformation. The basic load is the load which occurs during everyday operation, i.e. without someone falling. The exertion of a force of 1 kN is assumed, for example, as the basic load. Such a force is exerted on the rail to the maximum extent by a secured person when the person pushes against the rail. In order that the rail does not deform in the case of such a basic load of retaining forces and does not yield to the forces by tipping onto its weak side and then only the lesser section modulus becomes effective, the rail itself preferably has a closed, roughly square box section with horizontal and vertical section moduli of equal size. Two opposite-facing sides of the box section each have flanges lying in the plane of the side concerned, pointing in opposite directions. This side is called the xe2x80x9cflange sidexe2x80x9d in the following. A groove is formed between the flanges and this side is called the xe2x80x9cgroove sidexe2x80x9d of the rail in the following. The profile is symmetrical about both its vertical and its horizontal axis. One of the flange pairs serves to guide the runner while the other flange pair serves to mount the rail in the holders in a floating manner.
An advantage of the box section of the rail is that individual rail pieces can be joined together without any problems, by inserting, at the joint, a connection piece into the rail-ends to be joined and fixing it there by cross-bolts. The flanges are preferably hollow, i.e. the internal cavity of the rail also extends into the flange. The connection piece is developed so that it fills the cross-section of the entire cavity and accordingly also has flanges. The flanges of the rail are therefore also reinforced by the connection piece. The runner slides over such a joint without any problems. By including such a solid element of greater length into the hollow box section, the moment of resistance of the rail can be further increased. This can conveniently be e.g. in the center between two widely separated holders. The rail can also be reinforced by doubling it. This can be achieved by securing two rails together, the one flange pair of one rail then lying against a flange pair of the other rail.
The box section with two flange pairs can also be shaped into stable curved pieces. However, the preferred method for producing bends is to turn rings on a lathe with a profile which corresponds to the outer profile of the rail. Angle sections of the curved pieces are then separated out from these rings as necessary. These bends are made of solid material. Connection pieces with a central screw are fitted onto the end- or cut-surfaces of these rings. These connection pieces correspond to the joining pieces, but are however only roughly half as long. Because they are screwed on with a central, tangentially running screw, the connection pieces can be rotated about this central screw, under a greater load in order to remove the rotation resistance. Forces are thereby likewise absorbed if someone falls, the theoretical point for the rotation being created by screwing the connection piece tight against curved piece so that the plastic deformation of the rail piece adjoining it is largely avoided.
In order to improve the cornering motion, the flanges of the curved pieces are preferably somewhat thinner than those of straight rail pieces if the curve lies in the plane of the groove side of the rail. On the other hand, if the curve lies in the plane of the flange side of the rail, the flanges can optionally be selected somewhat lower in order to improve the cornering motion on the curved pieces. The double symmetrical profile of the rail simultaneously has the advantage that all rail courses can be realized with one vertical and one horizontal curved piece. As curved pieces can easily cause restrictions in sliding capacity and thus the running behavior of the runner, the curved pieces can also be completely coated with a plastic which improves the sliding capacity, e.g. PTFE.
To avoid contact corrosion at the interface between the rail made from stainless steel and the curved piece made from aluminium, the curved piece is preferably anodised as a whole or coated with a plastic, this function also being able to be fulfilled by the previously mentioned PTFE coating.
A further advantage of the profile of the rail being symmetrical about the horizontal and vertical axis is that if several people are secured on a rail, two people can pass each other if one person temporarily attaches his runner on the opposite-facing side of the rail at which the holders normally engage.
It can become necessary, in particular for greater rail lengths or tight enclosures, to provide expansion joints at intervals. For such expansion joints, joint pieces are used which are designed similarly to the above-mentioned connection pieces, onto which however only one rail piece is securely mounted. On the other hand, the other rail piece can travel for a certain distance on the joint piece. To this end, two opposing recesses are milled into the joint piece, in which groove blocks slide which are screwed fast to the movable rail piece. This design is advantageous vis-à-vis the oblong hole milled by the complete profile of the joint piece, as this could cause an excessive weakening of the material cross-section.
The holders are preferably formed as U-brackets, the closed end of which points downwards, one U-leg being fastened to the load-bearing structure, for example the masonry, while a claw, which clips round a flange pair of the rail, is fastened to the other U-leg. The claw is preferably centrally screwed fast or welded onto the U-leg so that the direction of force points through the center of the rail and no tilting moment is exerted on the rail. Because the closed side of the U-bracket points downwards, the U-bracket of the holder is opened in the event of a fall and can thus absorb drop energy and at the same time deform in the direction of pull. This deformation is facilitated by a vertical slit. Since forces pointing in the longitudinal direction of the rail do not act on the holder because of the movable mounting of the rail in the holder only light loads occur at the holder and no damage occurs at the facade in the event of a fall.
In the case of greater distances between the individual holders, it can be expedient to fasten the rail to the facade between two holders with simple fastening clips, the holders being e.g. stuck fast onto the facade. The fastening clips are conceived as holders with defined disengaging or releasing function and have no security function, but serve only to prevent a sagging of the rail and to introduce small retaining forces. They are intended to resist the above-mentioned basic load and hold the rail with up to a load of 1 kN for example. Instead of this, a holder with a corresponding releasing force can be attached to the facade. In the event of a fall, the rail loosens itself from the fastening clip or the entire holder from the fastening clips so that no damage occurs to the facade.
The runner functioning as an attachment point grasps around a flange pair and slides on this flange pair. To this end, it can be provided with a sliding, e.g. PTFE, insert or coating on the inside. To be able to better travel over the curved pieces of the rail, the side of the runner is provided with an insert only at the front and back ends of the runner. The insert is designed as a moulded piece having projections which click into corresponding openings in the body of the runner or are locked into it. The runner can also be coated with a slide coating likewise e.g. from PTFE according to a known process.
If there is no slide insert or coating, the runner is provided with an inwardly projecting, reinforced edge at its front and back end up to the rail. These reinforced edges lie against the rail. Through precise working of these edges the running properties of the runner can be improved, above all on curved pieces. These reinforced edges mean moreover that the inside of the runner is undercut and thereby does not engage with the rail, at least on straight rail pieces.
The device according to the invention can be used for safeguarding people against falling both on vertical climbing tracks and on horizontal sections. For vertical climbing tracks the runner is designed such that it blocks against a downward movement in the event of a fall.
In its simplest form the runner can be built up from two half-shells each of which grasps around a flange of the rail. The two half-shells are connected by a block which has a bore, in which the snap hook of the safety harness is suspended. Such a rigid runner can be placed only at end of the rail.
In another version, the two half-shells of the runner are provided with pipe bushing, with which the half-shells can be pushed onto at an axis. In their closed position, in which they tightly grasp around the flange of the rail, the half-shells are secured by a milled nut which can be screwed onto the end of the axis and by a safety stirrup. A swivellable arrester lever also sits in the piece of the axis lying between the half-shells. The lever has two lever arms of different lengths. An opening is provided on the longer lever arm, for suspending the snap hook of the safety harness while the length of the shorter lever arm is chosen so that it presses against the rail and thereby blocks the runner through friction locking on the rail in the case of a vertical climbing track if a downwardly directed force is exerted on the longer lever arm. The axis can be deflected in the form of an eccentric or offset in the area in which the lever arm is housed on it. By rotating the axis, the distance of the fulcrum of the lever arm can thus be shifted towards the rail and away from the rail. If the fulcrum is shifted towards the rail, the blocking function results. If, on the other hand, the fulcrum is shifted away from the rail the shorter lever arm does not impact against the rail in the event of a swivel motion and thus there is no blocking function. The axis can be fixed in both positions by means of guided safety stirrup. The effect of the guiding is that the safety stirrup can be swivelled into its fixed position only when the shaft is actually fixed. A runner developed in this manner with an engageable and disengageable arrester function and/or which can be opened and closed to connect at any desired point of a rail can also be used with other types of rails and security systems and thus represents an independent invention.
The arresting or blocking of the runner on the rail can take place through form-locking in the case of a vertical climbing track. To this end, catching stops, against which an arrester hook arranged on the lever arm of the runner runs, are arranged on the rail at regular intervals. Reference is made to DE-C-1 961 757 as regards details of such a form-locking arrester apparatus.